Shares started to rise as the event unfolded, reaching $668. Many investors decided to cash in at that point, since the stock fell back down to $657 after the event. But further trading drove the stock up to $669. It jumped still further in after-hours trading.

Yesterday, shares continued their ascent, closing at a record high of $682.98. Reaching new highs today, the stock is within a few points of capturing the $700 mark before day's end.

Some analysts recently upped their iPhone 5 sales forecasts. Analysts at Piper Jaffray believe Apple could sell anywhere from 6 to 10 million iPhone 5 handsets just in the few remaining weeks of September.

However, the investment firm said in a research note that it believes the stock will continue to rise for a week but then "expect shares to start working again once investors see the lines for the phone and going into earnings and a potential smaller iPad launch in October."

A recent report from financial firm Sanford C. Bernstein cautioned Apple investors that the stock is "relatively tepid" in the two weeks after a new product launch and that it typically underperforms over the subsequent two months.

Apple's recent gain is also due to more than just the new iPhone. The overall stock market surged yesterday after the Federal Reserve announced an aggressive new package aimed at stimulating the economy. The market has continued to pick up steam today, pointing to a healthy rally to close the week.